Safety lock for elevator doors



- Sept. 12, 1950 v. CARTA SAFETY LOCK FOR ELEVATOR nooRs 2 Sheets-Sheet 1 Filed Feb. 25, 1948 .5/ {ZZZ Sept. 12, 1950 v. CARTA SAFETY LOCK FOR ELEVATOR DOORS 2 Sheets-Sheet 2 Filed Feb. 25, 1948 hum r04 Kai/4 m 64,? ,f m Z21 1 Patented Sept. 12, 1950 SAFETY LOCK FOR ELEVATOR DOORS Virgilio Carta, Rome, Italy- Application February 25, 1948, Serial No. 10,847

In Italy May 3 0, 1942 Section 1, Public Law 690, August 8, 1946 Patent expires May 30, 1962 Claims. (01.187-31) This invention relates to safety locks for gates and doors of elevator shafts, and the like, provided with a self-acting locking device.

It is generally known that in order to guarantee the users safety, in compliance with the law, every gate or door for elevator shafts should be provided with a safety lock which prevents them from being opened unless the car is at the level of the corresponding fioor. The law prescribes further that every elevator must be provided with a self-acting blocking system to prevent or stop the motion of the .car in case the gates or doors are not perfectly closed.

In compliance with the above regulations, the locks serving for doors of elevator shafts, actually in use, are provided with the following safety implements:

(a) An electric contact interrupting the operating circuit and preventing normal motion of the elevator car when the gate with its lock is not perfectly closed;

(1)) A bolt-lock preventing the gate from being opened when the car is not facing the corresponding floor.

The devices above referred to are, as a rule, operated by springs which in the long run are liable to lose their elasticity and become ineflicient. The safety device actuated by them may become inoperative while the elevator continues operating, with serious danger to the user.

The object of the present invention is to provide a safety lock in which the springs upon which operation of the safety device depends, are eliminated and there is provided, to block the bolt, a pendulum, the raising of which is brought about by the action of a small roller gliding along a spline fitting to the elevator car and whereof the lowering into a locking position is ensured either by gravity or by forming said spline with such a profile as to tend to shift the pendulum itself back to its locking position after having raised the same into the relative opening position.

The said pendulum when in its lower position, blocks the motion of the safety bolt, thus locking the gate either by pressing directly upon the same or by immobilizing it through a set of levers.

Another object of the invention is to provide a device to secure, during the travel of the elevator car, the perfect irremovability of the blocking bolt from the position wherein the latter prevents the gate from being opened.

A further object of this invention is the provision of a device, operable only from the i iside of the shaft of the elevator, by means of which the opening of the gate from outside the elevator car can be prevented even while the car is stopping or passing in. front of the gate.

As regards the lock forming the subject matter of the present invention, two forms of practical embodiment have been contemplated, a first one in which the locking bolt has a horizontal motion, and a second one with rotary motion in a vertical plane. Both forms of practical embodiment may be fitted on doors and lattice gates with sliding motion and on swinging doors.

The lock forming the subject matter of the present invention is illustrated in the annexed drawings wherein: p

Figure 1 is a diagrammatic View of the elements for the raising of the blocking pendulum of the locking bolt of the lock;

Fig. 2 is a front elevation of a practical embodiment of the lock with the cover removed;

Fig. 3 is a fragmentary sectional view on the line IIIII[ of Fig. 2;

Fig. 4 is the front elevation corresponding to a second form of the lock with the cover removed; and

Fig. 5 is a fragmentary sectional view taken on line V--V of Fig. 4.

In the annexed drawings, the position of the single elements drawn with a full line is the position in which the same elements are to be found normally when the lock is closed. The positions drawn with a thin dotted line are, on the other hand, the positions in which the elements are temporarily shifted at the end of the their periodical displacements.

As shown in the drawings, I is the locking bolt. which rotates in a vertical plane about the pivot 2. The lower part of the said locking bolt is provided with two teeth 3 and 4. The upper part of the bolt is provided with a tooth 5 coming into engagement with the tooth 6 of the lever l apt to be swaying about the pivot 8. The bolt l carries a contactor 9 by means of an insulating member Ill. The contactor 9 establishes contact between the two blades H of the electric operating circuit of the elevator.

The teeth 4 and 5 engage the lever I2, the lower arm of which has the shape of a fork straddling the pivot 83 in order to establish a connection between the lever l2 and the bolt M. The front end I 5 of the said bolt is provided with an inclined cam surface IS. A spring i1 extends between lever i2 and the side of th casing of the lock. Each side wall of the casing is provided with .a guiding member l8, which, in cooperation,

serves to guide the bolt I during its motion. The bolt I, during its rotational opening movement, is stopped by abutment member I9 just when it is'in its topmost position, that is to say, in the position most advantageous for the successive dropping down. When the bolt I is in its closing position, on its upper part is applied pendulum which may swing around th pivot 2I when the roller 23 at the end of the arm 22 is positioned between the two profiled ribs 24 fitted onto the side of the elevator car. The profile of the two ribs 25 is such that they embrace and shift the small roller 23 and the arm 22, leaving it again in its initial position when the car moves away from the gate. On the pendulum Ell is carried, by means of the insulating element I9, switch 25 which, upon lowering of the pendulum 2t, bridges the terminals 26 of the winding of the electromagnet 2! which is in the operating circuit of the elevator, reducing thus, to its mini mum value, the work and hence the wear of the winding itself, inasmuch as the elevator operating current is flowing through the short-circuit, normally. However, the said current will have to flow through the winding of the said electromagnet only in the instant in which the passage of the car in front of the door raises the pendulum 29. Only then, will it be necessary to excite the electromagnet in order to efiect the raising of the armature 28, the head 29 of which wedges itself between the tooth 30 of the lever I and the abutment 3| fitted on the bottom face or the lock, immobilizing, by means of the lever l, bolt I which otherwise might rotate following the raising of pendulum 20. In such a way the possibility is eliminated that a person standing on a floor, at the level of which the car should not stop, might open the shaft at the very moment when the car is passing in front of the gate. On lever 3 is fitted contactor 9' serving to bridge contact blades I l which may be provided instead of contact 9-I I for the opening and closing of the elevator operating circuit.

Reference character 32 indicates an auxiliary stopping sector serving to prevent the car from being entered even when it is at the level of the desired floor.

The sector 32 is provided with two contactors 34 and 33 cooperating respectively with the blades 36 in the electric circuit which operates the elevator from outside the shaft and with the blades in a suitable electric circuit, serving for the operation of the luminous signals should the elevator momentarily be out of order. When the sector 32 is in the dotted line position, that is to say, when its upper part abuts against the lower portion of the lever I, it prevents the latter from being shifted downwardly. The shifting of the said stopping sector 32 is effected manually from inside the car, should the elevator become inoperable.

The operation of the lock illustrated in Fig. 2, and Fig. 3 is effected as follows: When the elevator car reaches the level of the floor, provided with such lock, the pendulum 29 is raised by means of the profiled ribs 24, to the dotted line position and at the same time, also the short cir-' cuits, at the terminals of the winding of the electromagnet, are interrupted.

Upon stopping the car, the electromagnet 2! no longer excited, drops the armature 28 which removes its headpiece from tooth SIB allowing the bolt I to be manually turned.

The spring I? normally maintains both the lever I2 and the bolt I4 in their position represented in full lines in the drawing, further it returns the parts to th same position as soon as, the causes, having brought about the momentary displacements, have terminated. One of such displacements takes place during the opening of the door or gate, through the raising of the locking bolt from position 1 into position 1'.

In this phase, teeth 3 and I of the bolt, engaging against the upper part of the lever I2 shift the latter into the position indicated with thin dotted line in the drawing, and since the lever i2 is connected through the pivot I3 with bolt I I, this in its turn undergoe a leftward shift, as long as the seat is not reached by its end I5 projecting, as a rule, from the edge of the mobile wing of the door. At the end of such a shift, the spring ii returns the two members I2 and I4 as far as their original position, and then, the upper end of the lever I2 is disposed in the path of travel of the tooth d of the bolt during dropping of the latter as soon as the person making use of the elevator removes his hand therefrom. This retains the bolt I, in its upper position 1'. The right hand end of the bolt I4 returns to project outwards from the edge of the door edge in such a way that, when the door is closed, bolt 54 engages by its chamfered face I6 against the fixed half-lock, causing thus the bolt M and consequently, the lever I2 to shift to remove the upper end of lever I2 away from tooth t so that bolt I will fall back again, closing the lock. The purpose of tooth 32a is solely to prevent the horizontal gliding of the bolt. It follows, therefore, that when the bolt is on gliding doors, the bolt cannot be withdrawn from the fixed half of the lock, hence the door cannot be opened as long as the bolt is not allowed its free rotation, which occurs only upon the withdrawal of the relative abutment provided by pendulum 2% that is to say, when the moving car reaches and stops in front of the door in question.

In the case in which the lock, shown in Figs. 2 and 3, is applied to a sliding door, there is no longer need of the member serving for the selfacting closure of th lock, which closure is then manually operated by the person using the elevator, after having made the door shift into its position of closure. Hence, in this case, the spring II, the lever I2 and the abutment I9 limiting the stroke of the bolt, may be eliminated.

In the practical embodiment of the lock illustrated in Figs. 4 and 5, there is a horizontally sliding locking bolt 5% urged to closed position by spring 5!. The head 52 of the bolt 50 is provided with a chamfered lateral face 56 in order to permit its use on swinging doors. The head 52 has a heart-shaped profile for engagement in the profile of two disc levers 57 and 51, which, while holding the bolt in its position of closure, also may be rotated by the said bolt, when the latter engages the projections SI of the levers. The disc levers 5i and 5'! are provided with teeth 58 and 58 which enter two grooves cut on the lever bearing contacting member 59 as well as in the blocking lever 60. The upper face of the blocking lever 68 is engaged by pendulum I8 on which is carried a ccntactor 62. The lever 59 carries the contactor 63 which closes the contacts 64 of the circuit operating the elevator. In the same circuit is inserted the electromagnet 65 which, upon excitation, raises the armature core 55 which, by means of the cable 61 and the pulley 68 rotates the lever 63 causing the tip I'll of the latter, to be wedged between the fixed abutment II and the left end of the contact carrying lever 59. The

fixation of this lever is necessary only during the time in which the car of the elevator is passing in front of a door, hence, in order to avoid undue wearon the winding of the electromagnet, the terminals of the latter are short-circuited, across the contactor 62 carried by the pendulum 18. Electric current flows through the winding only when during the travel, the car is passing in front of a door and when the pendulum 18 is raised. As has already been disclosed in connection with Fig. 2, an auxiliary stopping sector 12 is provided which has two contactors 14 and 13, one of which operates the electric circuit connected through blades 16 with the knobs controlling the elevator from the outside of the shaft, and the other by means of blades 15, actuates an electric circuit serving to transmit the luminous signal of the fact that the elevator cannot be used momentarily. The purpose and the operation of the sector 12 are analogous to those described in connection with Fig. 2.

The operation of the lock illustrated in the Figs. 4 and is as follows: When the elevator car reaches the level of a floor provided with such look, the pendulum 18 is raised as far upwards as the position indicated by the dotted line, whereupon the short circuit between the terminals of the winding of the electromagnet is interrupted, this fact brings about both the excitation of the electromagnet and the actuation of the disc looking lever 69. When the car stops, the electromagnet 65 now unexcited, drops the armature 66 whereby the tip of the lever 69 becomes disengaged from the switch'carrying lever 55. Hence, the bolt 50 may be operated from outside of the shaft of the elevator by means of the handle or key TI and slid horizontally to permit opening of the door. The bolt 50 sliding towards the left causes the two disc levers 57 and 51 to shift and, in turn, the other two levers 59 and 60, compelling them to rotate about their proper pivots until they reach the position represented in dotted lines. They are maintained in such position by gravity as long as the lock remains open. The bolt 50 is caused to glide towards the left as long as, in the case of winged doors, its right hand end does not overtake the edge 53 of the slot 54 cut in the bottom of the lock; and since the said edge is in register with the corner 55 of the fixed wing of the door, and the latter may be opened. In order to close the look again, in the case of a swinging door, it will be sufficient to press the mobile wing of the door against the fixed one of the same, until the chamfered face 56 of the bolt, butting against the corner 53 of the fixed wing of the lock, will cause the bolt to recoil, bringing about the compression of the spring 5]. The recoil of the spring pushes the bolt forward as soon as the two ends of the lock are in register again. On the other hand, in the case of a sliding door, the opening is brought about by a simple shifting towards the left whereas the closure by a simple shifting towards the right of the bolt. In both cases, the bolt during its stroke towards the right butts against the projection 6| of the disc levers 57 and 57' and, by causing them to rotate, operates the other two levers 6B and 59 compelling them to reassume their original position, that is, the position represented in the figure by full lines. through contact members 63-39, the closure of the electric circuit which operates the elevator, getting it ready-for restarting the motion. In both forms of invention referred to above, either all of the contacting members or only some of Consequently, the lever 59 effects,

them, instead of being arranged ina direction perpendicular to the plane of the-drawing, may also be comprised within planes parallel with the plane of the drawing.

The present invention has been illustrated and described according to a preferred form of practical embodiment, it being understood that constructive alterations might be brought thereinto practically without departing from the protective range of the subject matter claimed.

Having now. particularly described and ascertained the nature of the said invention and in what-manner the same is to be performed, I declare that what I claim is:

1. A safety look for sliding and swinging gates or doors affording access to elevator shafts, comprising a locking bolt provided with means for closing the electric circuit operating the elevator, a mechanical device to block opening movement of said bolt during travel of an elevator car between two successive floors, means to disengage the bolt either upon passage or stopping of the elevator car, a second electro-mechanical member to block the said bolt previously set free by the said mechanical device, an auxiliary stopping member manually operated from inside the elevator car to block the said bolt when the elevator is put out of operation, and means to render self-acting the closure of the lock when the gate or door is closed.

2. A safety lock according to claim 1 in which .the locking bolt is horizontally gliding.

3. A safety lock according to claim 1 in which the locking bolt is mounted for rotation within a vertical plane and is provided, on its lower portion, with a tooth.

4. A safety lock according to claim 1 in which the mechanical device serving to block the looking bolt during the travel of the elevator car from one floor to the other, includes a pendulum.

5. A safety lock according to claim 1 in which the means for disengaging said bolt upon the passage of stopping of the car at a floor, includes two guiding ribs, fitted on the elevator car and shaped to raise the said pendulum to set the bolt free, and to bring the pendulum itself back into its blocking position when the car has risen above the floor.

6. A safety lock according to claim 1 in which the electro-mechanical member serving to block the said bolt, correspondingly to the various floors, includes'an electromagnet which, when excited, provokes, through the motion of its core, the displacement of an element which, in its turn, butts against a contact carrying lever, in engagement with the said bolt, so as to prevent the latter from any movement.

'7. A safety lock according to claim 6 in which the terminals of the winding of the said electromagnet are short circuited across a contactor carried by the pendulum, which serves as the mechanical locking member of the bolt, said shortcircuit being interrupted in order to let the current flow through the windings of the electromagnet, only while the said pendulum remains raised at the passage of the car in front of a door.

8. A safety lock according to claim 1 in which the auxiliary locking member capable of being manually operated from inside the car includes a sector movable in a vertical plane and which sector, in one of its positions, immobilizes the bolt when the car stops in front of the door of a floor, said sector being provided, at its ends, with two alternatively operating electric switches which are included, one in the electric circuit operating the elevator from outside the shaft, and the other in a circuit providing a luminous signal, indicating the indisposability of the elevator, the latter circuit being closed when the sector is in position to block the bolt.

9. A safety lock for lattice gates or doors giving access to elevator shafts, according to-claim l in which the means to render self-acting the closure of the lock include a spiral spring engaged on the gliding bolt, which spring has the tendency 10 to return the latter, into its position of closure.

10. A safety lock for lattice gates and doors giving access to elevator shafts, according to claim 1 in which the means serving to render self-acting the closure of the lock, in the case of 15 8 a bolt rotating within a vertical plane, include: a spring operated lever, which lever connects the rotary motions of the locking bolt with the horizontal reciprocating motions of a sliding bolt, projecting normally from the mobile portion of the lock, which sliding bolt is compelled toreenter, under the impact given to it by butting against the corner of the fixed portion of the lock, when the door is being closed, producing the fall of the bolt from its elevated position, wherein the same is withheld by said lever.

VIRGILIO- CARTA.

N 0 references cited. 

